Rack-mounting a TU56

I have been given an H960 rack :-). I intend to use it for my PDP8/e system (currently piled up, not connected), which consists of the : PDP8/e processor, Full of cards, memory extension, EAE, 32KW core, boot diode matrix ROM, RK8e, RD8e, RX8e, PC8e, etc. PC04 paper tape punch/reader (acutally, I converted a PC05, but that doesn't matter here) RK05 (well, there's an RK8e in the backplane and I have a spare RK05 so I might as well use it) RX01 TU56 (single drive version, ths is not a TU55 as some have suggested!). Various PSUs and step-down transformer for the TU56 and PC04 I think I have the right slide rails for the first 4 units too... Anyway, does anyone have experience of rack-mounting a TU56? It clearly doesn't go on slide rails, it bolts directly to the rack (hinge down the front panel for access). I have the manuals from Bitsavers, they imply there is some kind of spacer block that goes under the TU56. Does anyone know what that is exactly so I can attempt to make one if it is needed. -tony